Rear Rider

Project Overview

Rear Rider is an alert system to notify cyclists of approaching objects and vehicles from behind them. The system utilizes a rear mounted camera and radar. The radar will determine if an object is approaching the cyclist, while the camera will utilize some machine learning to identify the type of object that is approaching. The Rear Rider will leverage cellular data from the smartphone to delegate the object identification to a third party to minimize local processing power and maximize battery life. Users will receive a combination of audio and/or visual alerts through the companion app to be installed on their smartphone, with customizable sounds and visual cues for alerts. Additionally, users will be able to filter their alerts based on the approaching object (i.e. omit alerts for approaching cyclists).

Team Members

• Jonathan Mendez
• Brock Morris
• Matthew O'Mara
• Bobby Palko
• Calin Pescaru
• Paul Sutton

Running main Rear Rider backend application.

Make sure the Raspberry Pi is configured to work as an access point on wlan0. The offical guide from Raspberry Pi has excellent step-by-step instructions.

sudo apt-get install python3-libcamera libgirepository1.0-dev gcc libcairo2-dev pkg-config python3-dev python3-venv gir1.2-gtk-3.0 libglib2.0-dev libdbus-1-dev libcap-dev python3-dbus libatlas-base-dev

# Create a virtual environment in python if not done so yet.
python -m venv .venv

# Edit .venv/pyenv.cfg to allow the virtual environment access to python packages downloaded from `apt-get install`.
# Add the following line to the aforementioned file:
include-system-site-packages = true

# Activate the virtual environment.
source .venv/bin/activate
# Install the required python packages from pip.
pip install -r ./requirements.txt
python ./rear_rider_device/main.py

Creating a systemd service

The Bluetooth server needs to be up and running when the Raspberry Pi boots in order to have a seamless connection and experience. To achieve this goal a systemd service needs to be created. In a text editor create a file, for example rearrider.service, and save it under /etc/systemd/system. Then, add the following lines:

[Unit]
Description=Bluetooth Server
After=bluetooth.service

[Service]
ExecStart=/home/pi/path_to_server
Restart=always

[Install]
WantedBy=bluetooth.target

Then, run these commands:

sudo systemctl enable rearrider.service
sudo systemctl daemon-reload

Now the Bluetooth server starts when the Pi boots. Also, Bluetooth has to be in discoverable mode so uncomment the line DiscoverableTimeout = 0 under /etc/bluetooth/main.conf.

Instructions on running the system

1. Make sure the Pi is up and running and that the OS is installed.
2. Clone the repo under /home/pi.
3. Follow the instructions under Running main Rear Rider backend application to install all the dependencies required.
4. Follow the instructions under Create a systemd service. This will create a service that starts automatically when Pi boots enabling the Bluetooth connection (as of right now create a service for the Bluetooth script under rear_rider_device/rear_rider_bluetooth_server/src/main.py).
5. Using Xcode, open the project under Rear Rider and install the application on your phone.
6. Reboot the Pi.
7. Now go to the iPhone's settings, Bluetooth, and connect to RearRiderPi4 once it's available.
8. Also, under the Wi-Fi settings, connect to the RearRider hotspot.
9. Now launch the Rear Rider app.

The application has three tabs. The first tab is the main view. Here the rider can see alerts when an object is approaching (TBD). The next view is the Live Streaming. The app will connect to the Pi over Wi-Fi and stream a live feed from the camera. The user has the option to record the streaming and to use ML to detect the objects in the feed. The last tab is the settings tab (TBD). At the top of the screen there are two icons that show if the Bluetooth and Wi-Fi connections are available by turning green.

Disabling Unnecessary Bluetooth Services

By default Raspbian's bluetooth service includes AVRCP, which is for the capability of streaming audio to the raspberry pi, but we do not require this. Also, the bluetooth service includes SAP (Sim Access Profile) which we do not make use of. Do the following to disable those features:

sudo systemctl edit bluetooth.service

Then, add the following lines to the indicated regions.

[Service]
# First clear the responsible variable.
ExecStart=
# Then reassign it with the aforemention plugins disabled.
ExecStart=/usr/libexec/bluetooth/bluetoothd --noplugin=sap,avrcp

Contributing

Updating requirements.txt

pip freeze --local > requirements.txt

include-system-site-packages = true in .venv/pyenv.cfg gives python access to all packages, especially those installed through apt. When a regular pip freeze > requirements.txt is called, all system packages are recorded in the requirements.txt file. The --local flag is needed in order to ensure that only the packages installed in the virtual enviroment are included! This issue was learned the hard way so be sure to remember this to not cause others problems.